Real-world analog signals such as temperature, pressure, sound, or images are routinely converted to a digital representation that can be easily processed in modern digital systems. In many systems, this digital information must be converted back to an analog form to perform some real-world function. The circuits that perform this step are DACs, and their outputs are used to drive a variety of devices. Radio frequency (RF) transmitters, loudspeakers, video displays, motors, mechanical servos, and temperature controls are just a few diverse examples. DACs are often incorporated into digital systems in which real-world signals are digitized by analog-to-digital converters (ADCs), processed, and then converted back to analog form by DACs. In these systems, the performance required of the DACs will be influenced by the capabilities and requirements of the other components in the system.
In theory, a DAC can operate at any frequency to provide an analog output corresponding to the digital data input. However, in the real world, errors and noise occur throughout the system, the effects of which increase with operating frequency. These effects may be code dependent and may result in harmonic distortion and harmonic spurs in the analog output signal. Improvements could be made with respect to addressing this issue.